Gophers and other rodents have presented problems for agriculture for millennia, and U.S. patents directed to solving problems related to gophers can be found that date back at least one hundred years. Simply put, there is a longstanding need for preventing gopher damage to plants, as further evidenced by multiple current research papers and products, none of which offer very effective or convenient solutions. Ironically, increased use of drip irrigation and other agricultural improvements may actually worsen such rodent problems, as the rodents are attracted by the water to the exact location of a plant's roots.
Proposed solutions include metal and plastic barriers, natural predators including owls, cats and snakes, and olfactory repulsions such as castor oil or predator urine. It is known for example to use wire mesh as a gopher barrier, and it is possible to create a wire mesh barrier that is placed into a hole in the ground prior to planting a plant in the hole. One item that can be purchased from some retail nurseries and at www.gopherbasket.com is a rectangular length of chicken-wire that has been folded in half and then crimped with a bar along its edges adjoining the fold, assuming the shape of an envelope which can then be opened at the edges furthest from the fold to form a strangely shaped wire mesh barrier that can be placed in a hole in the ground. It is alleged that the bar and fold can be bent and somehow formed into a round bottom, but the present inventor could not accomplish this, although it may be possible for someone else to bend the bar and wire into such a round shape with appropriate tools.
In the last half-century, biodegradable plant pots have become available. For example, Jiffy® Pots have been available since 1959, according to the website: http://www.jiffypot.com/. Biodegradable plant pots have advantages including the ability to transplant plants grown in the containers into the ground without disturbing the plants' roots. Another advantage of the biodegradable plant pots is that they generally serve to replace plastic pots that are formed from scarce resources (oil and energy), that are typically not recycled, and that last essentially forever. Some pots, such as Jiffy® Pots, are made from peat, which is itself a limited resource. Other commercially available biodegradable pots may be formed from recycled cardboard, ground plant fibers or the like that may be mixed with binding agents, placed in a mold and heated. Typically, pots made of such thick pressed cardboard do not disintegrate to let roots pass through easily for a number of years.
When a plant that had been growing in a plastic or metal container is placed in a hole in the ground that has a wire mesh gopher barrier installed, soil from the container may settle through the holes in the mesh, while the roots can be broken by the mesh. This type of settling is one of the ways that the plant's roots may be damaged during transplanting from such traditional containers. In contrast, when a plant that had been growing in a biodegradable pot is placed in a similar hole, the soil inside the pot is contained and so cannot settle to fill any spaces between the pot and the hole. Unfortunately, this can leave air gaps that can dry out the transplant or otherwise harm the roots, stunting or even killing the plant. Having wire mesh in the hole may exacerbate this problem. For example, when a chicken-wire envelope of the type described above is placed in a hole, in which it typically does not fit, the difference in shape between the pot, the hole and the chicken-wire envelope adds additional spacing between the pot and the hole. Moreover, the wire can make it more difficult for the ground surrounding the hole, which is often harder than the nursery soil in the pot, to disperse through the mesh to fill the spacing between the hole and the pot.
In one embodiment, a container for a plant is disclosed, including a wire mesh that is formed in the shape of a plant pot, and a layer of biodegradable material that is attached to the wire mesh in the shape of the pot. In this case, a single pot can conveniently offer plant roots both protection from gophers and protection from root damage during transplanting, with the biodegradable material quickly softening and/or decomposing to let the plant roots grow through the pot into the soil. Moreover, the problem of the plant drying out and dying after being planted in the ground due to air spaces surrounding the pot is ameliorated.
In one exemplary embodiment, the wire mesh may have holes that are in a range between ½ cm and about 3½ cm, preferably in a range between about ½ inch (1.3 cm) and about 1¼ inch (3.2 cm). The wire mesh can provide a frame for the biodegradable material, which allows the biodegradable material to be weaker or the pot to be larger than may otherwise be possible. For example, it could be difficult to use peat pots that are large enough hold a gallon or more of soil without breaking the pots. However, with an appropriate wire mesh providing a frame having greatly increased tensile strength, such pots could be much less prone to breakage.
Surprisingly, although the mesh may not disintegrate for years, tree, vegetable or other plant roots can grow through the spaces in the mesh and expand to swallow the wires without any noticeable damage to the plants. Certain wires, e.g. those containing iron or other minerals, may even provide beneficial nutrients that are slowly released. The wire of the mesh can be galvanized or otherwise treated to avoid decomposition, or can be made with materials designed to decompose over a certain time period. Once a plant, such as a tree, has reached a certain size, the roots at its base can be large enough to mostly avoid damage or at least death from gophers, which may prefer smaller roots that are tenderer and offer a greater proportion of growing material. Thus a wire mesh that disintegrates in several years may be beneficial for that type of plant.
In one exemplary embodiment, the wire mesh may extend up to several inches beyond the organic material of the pot at the top of the pot. This extension can be used as an above-ground gopher fence when the biodegradable material is buried in the planting hole to terminate approximately at ground level, and can provide a handle for the pot, which can be especially useful in freeing the pot from another pot that it is nested in. In one embodiment, the wire mesh that extends above the biodegradable material can be separated into a few sections, so that the mesh can be more easily folded inward toward the center, covering the roots from above. Alternatively, the biodegradable material can completely cover the wire mesh, including covering any sharp edges of wire that might exist if not manufactured carefully. Other embodiments contemplate having the wire mesh exposed on a surface of the pot, either a surface facing the interior of the pot (where the soil is to go), or an exterior surface (which is visible from outside the pot when the interior is filled with soil).
Integrated wire mesh/organic pots for vegetables or other annuals can be reused in subsequent years by nesting standard sized organic pots containing new vegetables in the recovered mesh pots, or simply planting the annuals in the ground within the mesh pots. Wire mesh pots, whether reused from a previous planting or new, can also be covered on the interior and/or exterior surface with household biodegradable material such as wet newspaper to form an integrated wire mesh/biodegradable pot.
Containers of wire mesh and biodegradable material can be tapered to be generally larger near a top of the container than near a bottom of the container, to better fit the growth of roots from the base of a plant and for aesthetic value, as well as to nest within other such containers. In various exemplary embodiments, such containers can have a circular horizontal cross-section, a substantially square horizontal cross-section or a substantially hexagonal horizontal cross-section. As mentioned above, a plant pot formed from the combination of wire mesh and biodegradable material has a number of synergistic advantages that are not found in any of the prior art of which the inventor is aware.